The invention relates to safety belt reeling means with a tightening device.
Belt reeling means have been proposed which comprise a drive which is activated in the event of an incident, the drive being spaced from a belt winding spindle of the belt reeling means and connectable thereto by means of a coupling in the event of actuation, a locking member eccentrically mounted on a driven disc, and capable of pivoting radially outwards in the event of actuation to engage with the teeth of a coupling member connected to the belt winding spindle.
Safety belt reeling means of this kind are described in applicant's U.S. Pat. No. 4,618,108 according to this publication, the drive mechanism for the belt winding spindle consists of a cable drive, wherein a cable wound on a cable reel is pulled off the cable reel by the linear movement of a piston connected to the cable in a cylinder and as a result the cable reel is set in rotation. The cable reel is coupled to the belt winding spindle by means of a locking member which is mounted on the cable reel and capable o pivoting radially outwards as a result of the inertia forces acting on it, said locking member coming into engagement with the teeth on a coupling disc integral with the spindle, as a result of which a connection is established which transmits force and torque between the cable reel and the belt winding spindle.
This known arrangement has the disadvantage that throughout the entire tightening movement determined by the rotation of the cable reel, drive energy must continue to be supplied to the piston since, if the drive energy were to be reduced or used up, the piston would no longer cause the cable reel to rotate, with the result that the tightening action described above, with the winding of a given length of belt onto the belt winding spindle, would not be achieved. The disadvantage of this is that the drive for the cable reel has to be comparatively large in construction since it is necessary to provide a path of travel for the piston which corresponds to the retraction of the belt in the region of the drive.
It is therefore an object of the present invention to improve a safety belt reeling mechanism of the aforementioned general type in such a way as to reduce the dimensions of the drive for achieving the tightening action.